title: The HLH-6 transcription factor regulates C. elegans pharyngeal gland development and function.
abstract: The Caenorhabditis elegans pharynx (or foregut) functions as a pump that draws in food (bacteria) from the environment. While the "organ identity factor" PHA-4 is critical for formation of the C. elegans pharynx as a whole, little is known about the specification of distinct cell types within the pharynx. Here, we use a combination of bioinformatics, molecular biology, and genetics to identify a helix-loop-helix transcription factor (HLH-6) as a critical regulator of pharyngeal gland development. HLH-6 is required for expression of a number of gland-specific genes, acting through a discrete cis-regulatory element named PGM1 (Pharyngeal Gland Motif 1). hlh-6 mutants exhibit a frequent loss of a subset of glands, while the remaining glands have impaired activity, indicating a role for hlh-6 in both gland development and function. Interestingly, hlh-6 mutants are also feeding defective, ascribing a biological function for the glands. Pharyngeal pumping in hlh-6 mutants is normal, but hlh-6 mutants lack expression of a class of mucin-related proteins that are normally secreted by pharyngeal glands and line the pharyngeal cuticle. An interesting possibility is that one function of pharyngeal glands is to secrete a pharyngeal lining that ensures efficient transport of food along the pharyngeal lumen.
authors.affiliation: Genes and Development Research Group, Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Ryan B
authors.initials: RB
authors.lastname: Smit
authors.forename: Ralf
authors.initials: R
authors.lastname: Schnabel
authors.forename: Jeb
authors.initials: J
authors.lastname: Gaudet
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000502:physiology*; D017173:Caenorhabditis elegans / Q000235:genetics / Q000254:growth & development* / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000502:physiology*; D018509:DNA, Helminth / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D053263:Gene Regulatory Networks; D017238:Genes, Helminth; D015801:Helminth Proteins / Q000378:metabolism; D009077:Mucins / Q000378:metabolism; D009154:Mutation; D010614:Pharynx / Q000254:growth & development* / Q000502:physiology*; D010641:Phenotype; D012689:Sequence Homology, Nucleic Acid
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D029742:Caenorhabditis elegans Proteins; D018509:DNA, Helminth; D015801:Helminth Proteins; D009077:Mucins; C517649:HLH-6 protein, C elegans